Primary prevention of teen smoking is a national public health priority and is central to comprehensive tobacco control. Effective health communication is part of this effort, including persuasive anti-smoking messages targeting young people about the health benefits of avoiding cigarette smoking and the harms of use. Anti- smoking messages are typically framed to emphasize either the benefits of smoking avoidance (gain-framed) or the costs of smoking to health (loss-framed). Indeed, the FDA recently acknowledged the importance of framed messages by requiring that graphic loss-framed health warnings appear on cigarette labels. Grounded in Prospect Theory, message framing suggests that gain-framed messages are superior to loss-framed messages for preventing teen smoking, but research in this area remains scarce. Understanding the effects of framed messages and the factors that influence message effects is critical to optimize their impact as a public health tool to prevent teen smoking. Primary care providers are in an excellent position to deliver smoking prevention information to teens, but provision of such information remains low. As a means to overcome barriers to office-based interventions, teens can be linked with evidence-based, online smoking prevention resources adjunct to pediatric primary care. Brief gain- and/or loss-framed messages may be an effective strategy to motivate teens to use evidence-based online prevention resources offered in this context, but little is known regarding the use of framed anti-smoking messages for this purpose. Our study seeks to develop and evaluate the effects of persuasive, framed messages on teens' utilization of an evidence-based online smoking prevention resource offered adjunct to primary care called A Smoking Prevention Interactive Experience (ASPIRE). Using a three-group experimental design, teens age 12 - 17 recruited via a large HMO will receive either a gain- or loss-framed message, or a generic message that will introduce teens to ASPIRE. After viewing messages, teens will have the option to access ASPIRE online immediately with continued access for 30-days. Teens will also receive weekly booster messages via mail and email, and will complete a 1-month follow-up assessment of ASPIRE use and smoking-related outcomes. We will examine the impact of framed messages on ASPIRE utilization and explore the moderating effects of social and psychological factors. We will also conduct preliminary analyses on the impact of framed messages and ASPIRE use on smoking susceptibility to inform planning of future studies in this area of research. This study is poised to provide critical insights regarding the ue of framed messages to prevent teen smoking. It will be among the first studies to investigate whether framed messages are effective for motivating teens to use online prevention resources offered adjunct to pediatric primary care, learning if framed messages work and for whom. Findings from this line of research may also be used to inform emerging national prevention efforts leveraging framed messages as a strategy to prevent youth smoking, such as the use of loss-framed health warning labels on cigarette packages. PUBLIC HEALTH RELEVANCE: Preventing teen smoking is a national public health priority and is critical to comprehensive tobacco control. This study seeks to develop and evaluate the effects of brief, framed messages for motivating teens age 12 - 17 to use an evidence-based smoking prevention web site offered adjunct to pediatric primary care. Brief, framed messages may be a highly efficient and effective approach to engage teens with proven online smoking prevention resources within this clinical context and could be adopted as a strategy to prevent teen smoking.